Systems and methods for determining carbon credits

ABSTRACT

A method of providing data relating to carbon sequestration, including the steps of:
         a) taking a soil sample at a selected location where a plant type has grown or is growing;   b) isolating phytoliths from the sample;   c) quantifying phytolithic organic carbon in the sample from the plant type to provide data; and   d) providing a projection for the data to support a carbon credit claim for the plant type growing at the location.

RELATED APPLICATION

This is a divisional of application Ser. No. 11/661,442, filed Aug. 7,2007, and Applicants claim priority under 35 USC §120 from theabove-identified parent application.

FIELD OF THE INVENTION

The present invention relates to systems and methods for determiningcarbon credits. The invention also relates to methods for determiningcarbon sequestration. The present invention also relates to methods fortrading carbon credits.

BACKGROUND TO THE INVENTION

The threat of global warming has caused increasing alarm, bothscientific and public, over the past two decades. Although debate isongoing, a number of leading environmental scientists believe thatglobal warming is a result of increased level of carbon dioxide andother greenhouse gases in the atmosphere. Studies have shown thatatmospheric carbon dioxide levels in the late 1950s were around 315 ppmand have been rising ever since. Recent data has shown that thecarbon-dioxide levels in the atmosphere had risen to about 376 ppm atthe end of 2003.

The increased levels of atmospheric carbon dioxide have been attributedlargely to increased burning of fossil fuels.

As a result of growing concern over the potentially devastating effectsof global warming, the United Nations Framework Convention on ClimateChange (UNFCCC) was adopted in 1992. By June 1993, the convention hadreceived signatures from 166 countries. The Kyoto protocol, which is aprotocol to the UNFCCC, was adopted at the third session of theconference of the parties to the UNFCCC in Kyoto, Japan, on 11 Dec.1997. The provisions of the Kyoto protocol attempt to regulate theoutput of carbon dioxide by member states that have signed and ratifiedthe protocol. Although a large number of countries have agreed to bebound by the provisions of the Kyoto protocol, neither Australia nor theUnited States of America are yet to ratify the protocol.

The levels of atmospheric carbon dioxide are controlled by two factors,these being (a) the amount of carbon dioxide being emitted into theatmosphere and (b) the amount of carbon dioxide being removed from theatmosphere into carbon sinks. Carbon sinks act as reservoirs for storingcarbon dioxide. Carbon sinks may include biomass (such as forest andcrops), plankton, soils, water bodies and geosequestration sinks. Thus,the net carbon dioxide emissions of any particular country arecalculated by determining total carbon dioxide emissions and totalcarbon dioxide taken up by carbon sinks.

The UNFCCC allows for a system of carbon trading. Under this system,parties who establish carbon sinks obtain a “carbon credit” in respectof the amount of carbon dioxide taken up into the carbon sinks. Thiscarbon credit can be traded to greenhouse gas emitters in order toenable the emitters to meet their targets under the Kyoto protocol.

It is known that as a result of plant growth, carbon based materialsform in a plant structure and the carbon based materials may return tothe soil to form carbon-containing deposits. There is establishedmethodology to determine soil organic carbon content, which is a factorof interest to those managing agricultural businesses. Most organicmaterial that is returned to the soil eventually rots and its carboncontent is emitted over a period of time as that material rots away.

Phytoliths, also referred to as plant opal, are silica features thatform in plants as a result of biomineralisation. Silica that occurswithin soils is taken up by the root system of a plant in the form ofsilicic acid (SiOH₄), and subsequently deposited throughout the intracellular and extra cellular structures of their leaf, stem and rootsystems. Piperno (1988), Phytolith Analysis: “An Archaeological andGeological Perspective” (Academic Press London) describes three sites ofsilica deposition within plant tissue. The sites comprise (1) the cellwall deposits, often called membrane silicification, (2) infillings ofthe cell lumen, and (3) in intercellular spaces of the cortex. The cellwall deposits often replicate the morphology of the living cells, whilethose forming in the lumen do not.

The presence of carbon within phytoliths was first discussed by theAustralian CSIRO scientists Jones and Milne (1963) “Studies of Silica inthe Oat Plant”, Plant and Soil XVIII(2):207 220. Following this initialresearch, a number of studies on carbon in fossil phytoliths wereundertaken. Such studies have concentrated on radiocarbon dating offossil phytoliths to establish stratigraphic chronologies forarchaeological and palaeobotanical research or δ13C isotope values todetermine palaeovegetation types based on C3 and C4 signatures. Thepresence of organic carbon in phytoliths has been recognised for itsrole in radiocarbon dating. Radio carbon dating has been conducted bythe inventors and it has been demonstrated that the carbon occludedwithin phytoliths in a soil depth of up to around 1.2 m was in the orderof 8,000 years old. The inventors' studies do not explore to a limitposition sequestration of carbon in phytoliths but there is no evidenceto suggest that there would be appreciable carbon release over muchlonger periods of phytolithic storage under most soil conditions.

It is also known that phytoliths can be separated from other organicfractions by heavy liquid flotation (for example, using a specificgravity of 2.35 gcm⁻³) or, as reported by one of the present inventors(i.e. Parr), acid digestion of the organic and carbonate component, thusleaving a silica residue (see one of the inventor's (i.e. Parr)publication “A composition of heavy liquid floatation and microwavedigestion techniques for the extraction of fossil phytoliths fromsediments.” Review of Palaeobotany & Palynology, 120 (2002): 315-336).

BRIEF DESCRIPTION OF THE INVENTION

In a first aspect, the present invention provides a method fordetermining the phytolithic organic carbon yield of a plant type at alocation or region comprising:

-   -   a) taking a sample of a plant type growing in the location or        region;    -   b) quantifying phytolithic organic carbon in the sample;    -   c) quantifying a total biomass of the plant type growing at the        location or region; and    -   d) determining a total amount of phytolithic organic carbon for        the total biomass of the plant type at the location or region.

The method of the first aspect of the present invention allows for thequantification of the phytolithic organic carbon yield of a particularplant type growing at a location or region. In this method, a sample ofthe plant type is collected from the location or region. The sample maycomprise a single example of the plant type or, more preferably, it maycomprise a number of specimens of the plant type. The sample is thenanalysed to determine the phytolithic organic carbon content of thesample. The phytolithic organic carbon content of the sample may bedetermined by any suitable process. For example, the sample may besubjected to low temperature combustion, to acid digestion or tomicrowave digestion.

Parr, J. F., Lentfer, C. J. and Boyd, W. E., (2001) “A comparativeanalysis of wet and dry ashing techniques for the extraction ofphytoliths from plant material.” Journal of Archaeological Science 28:875-886 and Parr, J. F., Dolic, V., Lancaster, G. and Boyd, W. E.,(2001) “A microwave digestion method for the extraction of phytolithsfrom herbarium specimens.” Review of Palaeobotany and Palynology, 116(2001): 203-212, both describe several methods for extracting phytolithsfrom plants. The entire contents of these articles are hereinincorporated by cross reference.

Once the phytoliths have been extracted from the sample, the phytolithscan be analysed to determine their carbon content (hereinafter referredto as phytolithic organic carbon or PhytOC) and thus the phytolithicorganic carbon content of the sample determined.

The carbon content of the extracted phytoliths can be determined by anumber of methods known to the skilled person. The present inventorshave also uniquely used a LECO carbon analyser instrument to determinethe carbon content of the extracted phytoliths.

Measurement of the carbon content of the phytoliths, often afterdescription of the phytoliths, usually involves organic carbondetermination, using the LECO instrument, dichromate digestion or othersuitable method.

The method of the first aspect of the present invention also involvesquantifying the total biomass of the plant type at the location orregion.

The total biomass of the plant type can be determined by a number ofdifferent methods known to be suitable by the person skilled in the art.These methods may include:

-   -   direct sampling;    -   indirect measurement using harvest data and known harvest        indices;    -   remote sensing techniques; and    -   using appropriate biomass accumulation curves (see, for example,        Montague et. al, “Carbon Sequestration Predictor for Land Use        Change in Inland Areas of New South Wales—Background User Notes,        Assumptions and Preliminary Model Testing, Version 2.0.”,        Research and Development Division State Forests of New South        Wales, Sydney 2003).

The skilled person will readily recognise and understand that the abovemethods and other methods may be used to determine the total biomass ofthe plant type growing at the location or region and further descriptionof such methods need not be provided.

Once the phytolithic organic carbon content of the sample has beendetermined and the total biomass of the plant type has also beendetermined, the total amount of phytolithic organic carbon present inthe plant type growing at the location or region can be simplycalculated. It will be appreciated that steps (b) and (c) may beconducted in any order.

If mixed vegetation is growing at the location or region, the method ofthe first aspect of the present invention preferably involves taking asample of one or more, preferably all, plant types growing at thelocation or region, determining the phytolithic organic carbon contentsfor each of the samples of plant types, quantifying the total biomass ofeach of the plant types growing at the location or region anddetermining the total amount of phytolithic organic carbon.

The carbon present in phytoliths remains sequestered within thephytolithic structure for a long period of time, in excess of severalthousand years. The present inventors have realised that phytolithsprovide an opportunity to sequester carbon. The present inventors havefurther realised that this provides an opportunity to obtain carboncredits by virtue of carbon becoming locked up in phytolithicstructures.

Accordingly, in a second aspect, the present invention provides a methodfor determining a carbon credit including the steps of:

-   -   a) taking a sample of a plant type growing in a location or        region;    -   b) quantifying phytolithic organic carbon in the sample;    -   c) quantifying a total biomass of the plant type at the location        or region;    -   d) determining a total amount of phytolithic organic carbon for        the total biomass of a plant type at the location or region; and    -   e) determining a carbon credit applicable to the location or        region based upon the total amount of phytolithic organic carbon        determined in step (d) above.

The carbon credit determined in the method of the second aspect of thepresent invention arises because the phytolithic organic carbon contentof the particular plant types growing at the location or regionrepresents carbon that is essentially permanently sequestered in thephytolithic structures. Thus, the phytolithic organic carbon is largelynon-biodegradable and represents carbon that has been essentiallyremoved from the atmosphere for millennia. The carbon credit calculatedaccording to this aspect of the present invention claims a credit forall carbon sequestered in the phytoliths.

If the location or region is subjected to cultivation or agriculture, inwhich crops of the plant type are periodically grown at regularintervals (e.g. one crop every year), the total phytolithic organiccarbon present in the crop represents a cumulative total of carbonpermanently sequestered from the atmosphere for each cropping cycle.Thus, a carbon credit equivalent to the phytolithic organic carbon totalof the crop minus that which would have been sequestered had the cropnot been cultivated can be claimed for each cropping cycle.

If the location or region is not subjected to regular cropping, theincrease in biomass on the location or region due to plant growth over aperiod of time can be claimed as a carbon credit. In this regard, itwill be understood that as the plants growing on the location or regionproduce greater above ground biomass, the amount of phytolithic organiccarbon in the plants will increase. This increase represents a carboncredit that can be determined in accordance with the method of thepresent invention.

It is also possible to determine phytolithic organic carbon arising froma particular plant type growing at a region or location by analysingsoil. In this regard, different plant types (including different plantfamilies and different plant species) have been found to have phytolithtypes that do not overlap in morphology with each other.

According to a third aspect, the present invention provides a method ofproviding data relating to carbon sequestration comprising:

-   -   a) taking a soil sample at a selected location where a plant        type has grown or is growing;    -   b) isolating phytoliths from the sample;    -   c) quantifying phytolithic organic carbon in the sample from the        plant type to provide data; and    -   d) providing a projection for the data to support a carbon        credit claim for the plant type growing at the location.

Step (c) may comprise a microscopic assessment of the phytoliths tocorrelate them with phytolithic structures derived from the plant typeof interest. The phytoliths may be isolated from the soil by using aflotation method, such as a dense medium flotation. Alternatively,phytoliths may be isolated from the soil by a microwave digested methodpioneered by one of the inventors Parr (2002) to remove soil anddegradable organic carbon from the soil sample to leave a residuecontaining the phytoliths, see Parr, J. F. (2002) “A comparison of heavyliquid floatation and microwave digestion techniques for the extractionof fossil phytoliths from sediments.” Review of Palaeobotany andPalynology 120 (3-4): 315-336. The entire contents of this reference areherein incorporated by cross reference.

The methods of the second aspect and third aspect of the presentinvention both provide methods for providing data to support a claim fora carbon credit. The second aspect utilises an analysis of a sample of aplant type to provide the necessary data whereas the third aspectutilises an analysis of the soil to obtain the determination of thephytolithic organic carbon content of plant types growing at thelocation.

It may also be possible to determine the amount of phytoliths producedat a location by analysing the phytolith content of material recoveredfrom the ground at the location. By determining phytolith content of thematerial on the ground at the location at spaced intervals, it ispossible to determine the amount of phytolithic material added to thematerial during the interval of time. Thus, in a fourth aspect, thepresent invention provides a method for determining the phytolithicorganic carbon accumulating at a location over a period of timecomprising the steps of:

-   -   a) collecting a sample of material from the ground at the        location;    -   b) determining the phytolithic organic carbon content of the        material;    -   c) using data determined in step (b) above, determining a total        phytolithic organic carbon content in the material at the        location;    -   d) after a predetermined period of time has elapsed, collecting        a further sample of material from the ground at the location;    -   e) determining a phytolithic organic carbon content of the        material in the sample;    -   f) determining a total phytolithic organic carbon content in the        material at the location from the data determined in step (e)        above; and    -   g) determining an amount of phytolithic organic carbon that has        accumulated at the location over the predetermined time interval        by subtracting the amounts determined in step (c) from the        amount determined in step (f).

The method of the fourth aspect of the present invention determines theamount of phytolithic organic carbon material present on the ground(such as in the soil) at the start of a time interval. At the end of apredetermined time interval, typically one year later (which correlatesto a growing cycle of plant types growing at the location), thephytolithic organic carbon content in the material collected from theground is again determined. As plants growing at the location during thepredetermined time interval are likely to have deposited phytolithicmaterial onto the ground during that time interval, the phytolithicorganic carbon present in material collected in the ground should haveincreased. The method of the fourth aspect of the present inventionmeasures that increase.

The material collected from the ground preferably includes leaf litter,humus and at least an upper layer of the soil.

In a fifth aspect, the present invention provides a method forsequestering carbon comprising the steps of determining one or moreplant types having enhanced production of phytolithic organic carbon andcultivating the one or more plant types at a location or region toincrease the phytolithic organic carbon production at the location orregion.

The method of the fifth aspect may further involve the step of replacingexisting growing biomass at the location or region with the one or moreplant types having enhanced production of phytolithic organic carbon. By“enhanced production of phytolithic organic carbon”, it is meant thatthe production of phytolithic organic carbon by the one or more planttypes is higher than for the existing plant types growing at thelocation or region. Most native grasses, wetland herbaceous plants suchas giant rush, cyperaceae species and domesticated plants such asbarley, corn, rice, sugar cane and wheat, have high levels ofphytoliths.

Other plants have high phytolithic content but the occluded carbonwithin the phytoliths has not been calculated, these plants are listedbelow (taken from J. F. Parr, L. A. Sullivan, Soil Biology andBiochemistry 37 (2005): 117-124 121).

Abundance of extracted phytoliths from herbarium specimens assessedvisually on glass slides at 400× magnification from plant speciesoccurring at Numundo and Byron Bay sites

High

Asteraceae: Vernonia cinerea (L.) Less., Blechcaceae: Blechnum indicucmBurm. F., Cyperaceae: Gahnia sieberana Kunth., Moraceae: Artocarpuscumingiana Trec., Ficus coronata Spin., Myrtaceae: Eucalyptus robustaSmith, Pandanaceae: Pandanus tectorious Solms., Poaceae: Bambusaforbesii (Ridl.) Holttum, Brachiaria brizantha (Hoscht. Ex A. Rich) Stapf., Buergersiochloa macrophylla S. T. Blake, Blumea Supp., Coixlachryma-jobi L., Hetaropogon triticus (R. Br) Stapf. Ex Cralb, Imperatacylindrica P. Beauv., Imperata exaltata (Roxb.) Brogn., Ischaemumpolystachyum (L.), Polytoca macrophylla Benth., Saccharum officinarum(L.), Saccharum robustum (L.), Seteria sphacelata (K. Schum.) Stapf. &C. E. Hubb, Schizostachym brachycladum (Blanco) Mer., Themeda arguens(L.) Hack, Thysanolsara maxima (Roxb.) O.K., Pteridophyta: Diplaziumesculentum (Retz.) Sw., Rubiaceae: Massaenda ferruginea K. Sch. Var.scandens Val., Timonius sp., Scrophulariaceae: Buchnera tumentosa Bl.,Simaroubaceae: Ailanthus integrifolia Lamk.

Medium

Annonaceae: Annona muricata L., Arecaceae: Areca catachu L., Caryotarumphiana Mart., Cocas nucifera L. Burseraceae: Canarium indicum L.,Combretaceae: Terminalia catappa L., Cucurbitaceae: Bryophyllum pinnatum(Lamk) Kurz., Luffa cylindrica (L.) Roem., Cyperaceae: Cyperus kyllingiaEndl., Moraceae: Ficus nodosa Teysm. & Binn, Ficus papus Peekel, Ficuspungens Reinw. ex Bl., Myrtaceae: Eucalyptus maculata Hook.,Leptospermum sp., Piperaceae: Piper betal L., Pteridophyta: Nephrolepishirstulata (Forst.) Presl, Rubiaceae: Massaenda ferruginea K. Sch. Var.scandens Val., Rutaceae: Euodia hortensis J. R.&G. Forst., Sapotaceae:Burckella obovata (Forst.) Pierre, Simaroubaceae: Quassia indica(Gaertn.) Nooteboom

Low

Acanthaceae: Hemigraphis reptans (Forst. F.) And. ex Hemsley,Amaranthaceae: Cyathula prostrata Bl., Anarcardiaceae: Dracontomelon dao(Blanco) Merr& Rolfe, Spondias dulcis Soland. ex Forst., Annonaceae:Cananga odorata Hook., Apocynaceae: Alstonia scholaris R. Br., Cerberamanghas L., Ichnocarpus frutescens (L.) R. Br., Araceae: Colocasiaesculenta (L.) Schott., Schismatoglottis calyptrata (Roxb.) Zol & Mor.,Pothos helwigii Engl., Araliaceae: Polyscias cummingiana (Presl.)F.-Vill., Arecaceae: Licuala peckelii Laut., Metroxylon sagu Rottb.,Nypa fruticans Wurmb., Aristolochiaceae: Aristilochia tagala Cham.,Barringtoniaceae: Barringtonia asiatica L., Barringtonia novae-hiberniaeLaut., Boraginaceae: Cordia subcordia Lamk., Caryophyllaceae: Drymariacordata (L.) Willd. Ex Roem& Schult., Convolvulaceae: Ipomea batatus L.,Ipomea congesta R. Br., Cycadaceae: Cycus rumphii Miq., Cyperaceae:Mapanea macrocephala (Gaud.) K. Sch., Dioscoreaceae: Dioscoreapentaphylla L., Ebenaceae: Diospyros peekelii Laut., Euphorbiaceae:Macaranga aleuritoides F. Muell., Macaranga tararius (L.) Muell.-Arg.,Macaranga urophylla Pax & Hoffm., Manihot esculenta Crantz., Fabaceae:Canavalia rosea (Sw.), Casia alata L., Flagallariaceae: Flagallereagigantia Hook. f., Flagallarea indica L., Flacourtiaceae: Homaliumfoetidum (Roxb.) Benth., Pangium edule Reinw., Gnetaceae: Gnetum gnemonL., Gnetum latifolium L., Goodeniaceae: Scaevola taccada (Gaertn.)Roxb., Hernandiaceae: Hernandia nymphaefolia (presl) Kubitski,Lamiaceae: Ocimum basilicum L., Lauraceae: Cassytha filiformis L.,Litsea grandiflora Teschn., Liliaceae: Cordyline fruiticosa (L.) A.Chev., Cordyline terminalis Kunth, Malvaceae: Hibiscus manihot L.,Hibiscus tiliaceus L., Sida rhombifolia L., Marantaceae: Donaxcanniformis (Forst.) K. Sch., Melastomataceae: Osbeckia chinensis L.,Moraceae: Artocarpus cumingiana Tree., Musaceae: Heliconia bihai L.,Heliconia indica Lamk., Musa accuminata (simons), Musa becarrii(simons), Musa erecta (simons), Musa paradisica L., Musa peekelliiLaut., Musa schizocarpa (simons), Musa truncata var. horizontalisHoltlum., Ensete calosperma F.U.M., Myrtaceae: Syzigium bevicymum(Diels) Merr. & Perry Syzigiummalaccence (L.) Merr. & Perry,Nyctaginaceae: Pisonia longirostris Teys. & Binn., Orchidaceae:Dendrobium bifalce Lindl., Dendrobium peekelii schltr., Piperaceae:Piper mestorii F. M. Bail., Piper peekelii C. DC., Pittosporaceae:Pitosporum ferrugineum Ait., Podocarpaceae: Dacrycarpus imbricatus Bl.,Proteaceae: Banksia sp., Pteridophyta: Bolbitis quogana (Gaud.) Ching,Rhamnaceae: Alphitonia macrocarpa Mansf., Alphitoria molaccana Reiss. exEndl., Rhizophoraceae: Brugiera gymnorrhiza (L.) Lamk, Rhizophoraapiculata Bl., Rosaceae: Cyolendophora laurina (A. Gr.) Kosterm., Rubusrosaefolius Sm., Rubiaceae: Uncaria bernaysii F. Muell., Sapindaceae:Pometia pinnarta J. R. & G. Forst., Scrophulariaceae: Linderniacrustaceae (L.) F. Muell., Solanaceae: Datura metal L., Solanumerianthum D. Don., Solanum torvum Sw., Sterculiaceae: Heritieralittoralis Dryand ex W. Ait., Kleinhohia hospita L., Melochia odorata L.f., Urticaceae: Dendrocnide warburgii (Winkl.) Chew, Leukosykecapitellata Poir., Pipturus argenteus (Forst.) Wedd., Verbenaceae:Premna serratifolia L., Xanthorrhoeaceae: Xanthorrhoea resinosa Pers.High: >66% cover of slide, Medium: >33 to <66% cover, and Low: >1 to<33% cover.

In a sixth aspect, the present invention provides a method fordetermining carbon credits comprising:

-   -   a) determining one or more varieties of plants that can be used        to enhance phytolithic organic carbon production;    -   b) establishing phytolithic organic carbon sequestration data        for the one or more varieties of plants under environment        conditions appropriate to a selected location;    -   c) arranging cultivation of at least one of the varieties of        plants in the location; and    -   d) determining carbon credits on the basis of the phytolithic        organic carbon sequestration data and cultivation practice.

This aspect may also involve breeding varieties of plants that can beused to enhance phytolithic organic carbon production. In the context ofthis specification, breeding of plants includes conventional plantbreeding techniques, genetic manipulation techniques, tissue culturetechniques and indeed any other technique that results in new varietiesof plants being developed.

In a seventh aspect, the present invention provides a method forclaiming carbon credits including the steps of:

-   -   a) determining an amount of phytolithic organic carbon arising        from vegetative biomass growing on a location or region;    -   b) determining an amount of phytolithic organic carbon arising        from cultivation of one or more plants having enhanced        production of phytolithic organic carbon on the location or        region;    -   c) cultivating the one or more plants having enhanced        phytolithic organic carbon on the location or region; and    -   d) claiming a carbon credit based upon the difference between        the amount determined in step (b) and step (a).

Step (a) suitably determines an amount of phytolithic carbon produced bythe vegetative biomass growing at the selected location or region in aspecified period of time. For example, in low lying wetlands around theByron Bay area of Australia, the present inventors have established thatthe natural vegetation sequesters carbon at a rate of 0.9 gCm² per year.Step (b) suitably determines an amount of phytolithic organic carbonarising from cultivation of one or more plants having enhancedproduction of phytolithic organic carbon at the selected location orregion in a similar period of time. A claim for carbon credits can bemade where the amount determined in step (b) is larger than the amountdetermined in step (a).

In an eighth aspect, the present invention provides a method forclaiming carbon credits using formula (1):

A=B ₁ −B ₂  (1)

where:

A=an amount of carbon that is claimed as a carbon credit fromcultivating a particular plant type in a specified location or region;

B₁=an amount of carbon sequestered in phytoliths produced by the planttype at that selected location or region in a specified period of time;and

B₂=an amount of carbon sequestered in phytoliths prior to thecultivation of that plant type at that selected location or region in asimilar period of time.

Where B₁ exceeds B₂, a carbon credit can be claimed.

In this aspect of the present invention, cultivation of the plant typeincludes one or more of the following: choice of plant type or cultivar,the addition of amendments to improve growth rate of the plant type,intensive growing of the plant type, growing of the plant type underartificial conditions (such as in a greenhouse, using hydroponics, usingan aquaculture method, etc.) or any other practice aimed at effecting orincreasing the amount of phytolithic carbon sequestration.

In this aspect of the present invention, B₁ may be calculated inaccordance with formula (2) below:

B ₁=(PhytOC yield)×(vegetative biomass production)  (2)

where:

PhytOC yield=the proportion of biomass of the plant type that exists asphytolithic organic carbon during the specified period of time; and

vegetative biomass production=the amount of vegetative biomass producedduring the specified period of time.

The PhytOC yield could be either determined directly for a specifiedtime period for a selected location or region by any of the methodsdescribed herein above in this specification. Alternatively, it may beestimated using previous PhytOC data for the specified plant type.

B₂ may be calculated in accordance with formula (3):

B ₂=(previous PhytOC yield)×(previous vegetative biomassproduction)  (3)

where:

previous PhytOC yield=the proportion of vegetative biomass of thepreviously cultivated plant type(s) that existed as phytolithic organiccarbon; and

previous vegetative biomass production=the amount of vegetative biomassproduced prior to the cultivation of that plant type at that selectedlocation or region in a similar period of time.

B₂ is the amount of carbon sequestered in phytoliths and can bedetermined (1) from that which existed prior to the cultivation of aplant type (either by determination or estimation) or (2) using anestimated global average PhytOC for vegetation (which is approximately0.9 gCm² per year as determined by the present inventors).

In a ninth aspect, the present invention provides a method forsequestering carbon including the steps of

-   -   a) treating vegetative biomass to produce a mass containing        phytoliths;    -   b) sequestering the phytoliths by using the mass produced in        step (a) as a landfill, a road base or as a component in a        manufacturing process;    -   c) determining the carbon content of the phytoliths in the mass;        and    -   d) claiming a carbon credit based upon the determined carbon        content.

Step (a) may comprise simply harvesting growing plants, or it may alsocomprise further treatment of harvested plants. For example, the furthertreatment may include low temperature combustion to produce an ashcontaining phytoliths. Alternatively, it may comprise an acid digestionor microwave digestion to extract phytoliths from the vegetativebiomass.

Step (b) may comprise placing the mass containing the phytoliths into alandfill and, optionally, covering the mass with soil or other wastedisposed in the landfill. Alternatively, the mass may be used as acomponent in a road base material. This is effective in locking up thephytoliths because the road base material is covered by bitumen, asphaltor concrete during construction of the road. As a further alternative,the mass of material containing the phytoliths may be used as acomponent in a manufacturing process. Some examples of suitablemanufacturing processes include cement manufacture, concretemanufacture, manufacture of building materials such as clay bricks,concrete bricks, sheeting material or other building material.

Government regulations or international treaties relating to claimingcarbon credits may require that carbon sequestration for a location orregion be determined at a specified starting date (for example, theUNFCCC currently specifies 1990 as a start date), determining carbonsequestration at a later date, with any difference in carbonsequestration leading to the claim for a carbon credit. Accordingly, thestep of determining a carbon credit in the various aspects of thepresent invention may include the step of determining carbonsequestration arising from PhytOC at the location or region at aspecified start date and subtracting that from the determined carbonsequestration arising from PhytOC at the location or region at a laterdate.

It will also be realised that other factors besides PhytOC sequestrationmay be included in the calculation of a carbon credit, for example,carbon taken out of the atmosphere by additional vegetative biomassgrowing at the location or region. Thus, the carbon credit claimed byvirtue of PhytOC sequestration may form but a part of an overall carboncredit claim.

The carbon credits may be traded as desired. Thus, the present inventionalso includes trading systems and methods for trading carbon creditscalculated in accordance with the various aspects of the presentinvention.

The methods of the present invention that relate to determining carboncredits are based on recognising the concept that carbon sequestrationin phytoliths can be validated, quantified and applied to anagricultural based business whereby useful economic benefits to theoperator of the agricultural business can be substantiated. In someaspects, the concept includes establishing the phytoliths in soil orplant material in a validated manner whereby an economic benefit interms of a claim for carbon credits can be made.

Preferred embodiments of some aspects of the invention are those wherevalidated data is developed to establish optimal or near optimalagricultural operations to predict carbon sequestration based onhistorical data or by analysis. In preferred embodiments of some aspectsof the invention, the method includes making a claim for carbon creditsbased on the data for carbon sequestration related to the plant type andto the location at which the plant type is growing or is to be grown.Validation of the carbon credit claim may take into account specificgrowing conditions and, where possible and relevant, include modifyingthe growing conditions, for example, by alteration of moisture levels,pH and/or fertiliser regimes towards optimising phytolithic carbondevelopment in the plant structure.

In some aspects, the methodology of the present invention may includefurther validating measurements in relation to a growing cycle toestablish biomass generated and phytolithic carbon sequestration tofurther authenticate and validate the claim.

It is acknowledged that natural environments such as forest and, inparticular, rainforests, will sequester carbon, some of which is in thephytolithic and therefore secure sequestered form. However, theinventors point out that other species, notably grass crop speciesincluding wheat, are grown most extensively for food production andpoint out the considerable efficiency of these species in producingphytolithic organic carbon. The inventors point out that the role ofbiogenic silica phytoliths in carbon storage and its validity to carbonsequestration and carbon credit claims has been overlooked. Based onthis realisation the inventors propose optimisation of agriculturalbusiness approaches to establish and preferably optimise carbonsequestration for economic benefits.

The inventors' investigations demonstrate that particular types ofhabitats and plant species produce different quantities of phytolithsunder various conditions. Data has been currently accrued for coastalplains, foreshore areas, rainforest, peatlands, wetlands and woodlandhabitats under a range of conditions from the wet tropics of Papua NewGuinea, the Torres Strait Islands, coastal northern New South Wales andits hinterland. Results showing that of an initial 81 plant familiescomprising 213 species tested some 59 families and c. 100 species werefound to have diagnostic phytoliths types that did not overlap inmorphology with each other.

Furthermore the inventors have established that the above habitats andplant species retain variable amounts of carbon (PhytOC) within thephytoliths they produce (Tables 1 & 2). Thus from the data, favourableconditions for phytolith production and therefore carbon sequestrationcan be calculated for specific types of land.

Once a phytolith is isolated from the surrounding plant material and isburied in nature it is resistant to deterioration and can retain thesequestered carbon for periods exceeding 8,000 years. Thus the inventorshave demonstrated through field and laboratory experiments that carboncan be sequestered in a range of natural environments as PhytOC. Wheresuch environments are human induced under the most optimal conditions,phytolith yield and in particular PhytOC can be predicted and ultimatelyexploited. This follows from traditional farming practice where optimalconditions are observed from nature and manipulated to enhanceexploitation of a given crop.

TABLE 1 Summary of various habitats with the same annual rainfall,various soil pH levels, different dominant plants species within thesehabitats and the calculated carbon sequestered in the phytolith contentextracted from 0.25 grams of soil from each habitat. annual Dominantplant % Habitat rainfall soil pH family PhytOC Open coastal grassland4,000 mm 4.87 Poaceae 0.5105 Open grassland 4,000 mm 6.43 Poaceae 0.4424Disturbed herbaceous 4,000 mm 6.96 Amaranthaceae 0.1900 wetlandHerbaceous wetland 4,000 mm 6.69 Cyperaceae 0.2873 Peatland 4,000 mm3.68 Restionaceae 5.0535

TABLE 2 Example of phytolith carbon content from rice Oryza sativa andspinifex grass Triodia reptins extracted from plant material usingmicrowave digestion and analysed by LECO total carbon analysis. Species% PhytOC Oryza sativa 0.9 Triodia reptins 1.0

Those skilled in the art will appreciate that the present invention maybe subject to variations and modifications other than those specificallydescribed. It is to be understood that the present invention encompassesall such variations and modifications that fall within its spirit andscope.

1. A method of providing data relating to carbon sequestrationcomprising: a) taking a soil sample at a selected location where a planttype has grown or is growing; b) isolating phytoliths from the sample;c) quantifying phytolithic organic carbon in the sample from the planttype to provide data; and d) providing a projection for the data tosupport a carbon credit claim for the plant type growing at thelocation.
 2. The method as claimed in claim 1 further comprisingcalculating a claim for a carbon credit from the projection of step (d).3. A method for sequestering carbon comprising the steps of determiningone or more plant types having enhanced production of phytolithicorganic carbon and cultivating the one or more plant types at a locationor region to increase the phytolithic organic carbon production at thelocation or region.
 4. The method as claimed in claim 3 furthercomprising the step of replacing existing growing biomass at thelocation or region with the one or more plant types having enhancedproduction of phytolithic organic carbon.
 5. A method for determiningcarbon credits, comprising: a) determining one or more varieties ofplants that can be used to enhance phytolithic organic carbonproduction; b) establishing phytolithic organic carbon sequestrationdata for the one or more varieties of plants under environmentconditions appropriate to a selected location; c) arranging cultivationof at least one of the varieties of plants in the location; and d)determining carbon credits on the basis of the phytolithic organiccarbon sequestration data and cultivation practice.
 6. The method asclaimed in claim 5 further comprising breeding varieties of plants thatenhance phytolithic organic carbon production.
 7. A method for claimingcarbon credits including the steps of: a) determining an amount ofphytolithic organic carbon arising from vegetative biomass growing on alocation or region; b) determining an amount of phytolithic organiccarbon arising from cultivation of one or more plants having enhancedproduction of phytolithic organic carbon on the location or region; c)cultivating the one or more plants having enhanced phytolithic organiccarbon on the location or region; and d) claiming a carbon credit basedupon the difference between the amount determined in step (b) and step(a).
 8. A method for claiming carbon credits using formula (1):A=B ₁ −B ₂  (1) where: A=an amount of carbon that is claimed as a carboncredit from cultivating a particular plant type in a specified locationor region; B₁=an amount of carbon sequestered in phytoliths produced bythe plant type at that selected location or region in a specified periodof time; and B₂=an amount of carbon sequestered in phytoliths prior tothe cultivation of that plant type at that selected location or regionin a similar period of time.
 9. The method as claimed in claim 8 whereinthe cultivation of the plant type includes one or more of the following:choice of plant type or cultivar; the addition of amendments to improvegrowth rate of the plant type; intensive growing of the plant type; orgrowing of the plant type under artificial conditions.
 10. The method asclaimed in claim 8 wherein B₁ is calculated in accordance with formula(2) below:B ₁=(PhytOC yield)×(vegetative biomass production)  (2) where: PhytOCyield=the proportion of biomass of the plant type that exists asphytolithic organic carbon during the specified period of time; andvegetative biomass production=the amount of vegetative biomass producedduring the specified period of time.
 11. The method as claimed in claim8 wherein B₂ is calculated in accordance with formula (3):B ₂=(previous PhytOC yield)×(previous vegetative biomassproduction)  (3) where: previous PhytOC yield=the proportion ofvegetative biomass of the previously cultivated plant type(s) thatexisted as phytolithic organic carbon; and previous vegetative biomassproduction=the amount of vegetative biomass produced prior to thecultivation of that plant type at that selected location or region in asimilar period of time.
 12. A method for sequestering carbon includingthe steps of a) treating vegetative biomass to produce a mass containingphytoliths; b) sequestering the phytoliths by using the mass produced instep (a) as a landfill, a road base or as a component in a manufacturingprocess; c) determining the carbon content of the phytoliths in themass; and d) claiming a carbon credit based upon the determined carboncontent.
 13. The method as claimed in claim 12 wherein step (a)comprises harvesting growing plants.
 14. The method as claimed in claim12 wherein step (a) comprises further treatment of harvested plants toproduce a mass containing phytoliths having a higher concentration ofphytoliths than the harvested plants.
 15. The method as claimed in claim14 wherein the further treatment comprises low temperature combustion toproduce an ash containing phytoliths or an acid digestion or microwavedigestion to extract phytoliths from the vegetative biomass.
 16. Themethod as claimed in claim 12 wherein step (b) comprises placing themass containing the phytoliths into a landfill and, optionally, coveringthe mass with soil or other waste disposed in the landfill, or using themass as a component in a road base material, or using the mass ofmaterial containing the phytoliths as a component in a manufacturingprocess.